One of the most flexible options for accessing a dataset directly is via an ‘Application Programming Interface’ (API).  This allows third party developers to create unique or tailored interfaces to one or more systems enabling them to be cross searched by end users in a uniform manner. Such interfaces may vary from standalone applications to modules for large scale integrated library systems. Common protocols used to offer API access include REST and SOAP.

In addition to any technical systems development work required, NBAs wishing to offer API access would need to offer potential developers current details of the API specification for their particular database e.g. the OCLC WorldCat Search API. NBAs should also ensure that they take account of any potential security implications arising from granting access to their datasets to third parties.